Electrical switching component

ABSTRACT

An apparatus including an electrical switching device to control current to a load and a second case arranged to substantially encapsulate the electrical switching device. The electrical switching device includes a first case; a plurality of contacts disposed in the first case; and an opening in the first case disposed to expose the contacts. The second case is arranged to duct a blast from the opening of the first case of the electrical switching device.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from, and is a divisional of, U.S.patent application Ser. No. 12/562,732 filed Sep. 18, 2009.

BACKGROUND

Electrical switching devices such as relays and circuit breakers areoften encapsulated in cases to protect the operating mechanisms fromdust, moisture and other environmental conditions, and to preventtechnicians and others from contacting live electrical parts. Certainoperating conditions may cause a blast or build-up of hot, pressurizedgases and other materials within the case. For example, short circuitsmay cause contacts in relays or circuit breakers to melt or explode,thereby releasing hot gases and molten metal. As another example, anover current condition may cause the contacts in a circuit breaker toopen, which may in turn, create a momentary arc between the contacts.The arc releases a blast of ionized air.

If the blast is not vented from inside the case, it may damage, destroyor interfere with the operation of the electrical device and/or causethe case to rupture, thereby scattering dangerous blast products whichcan, in turn, cause a fire and/or create an electrical shock hazard.Thus, cases for electrical switching devices are often provided with avent in the top or side of the case to enable a short circuit or othertype of blast to escape from within the case. While venting the case maysolve certain problems with the electrical switching device, it oftencauses other problems. For example, in an electrical enclosure housingmultiple components, a blast from one device may be directed at anotherdevice, which in turn is damaged or destroyed by the blast. In addition,within the electrical switching device, the blast can short high voltageterminals with low voltage circuitry, creating a potential hazard.

Some other previous efforts to accommodate a blast from an electricalswitching device have involved the use of complicated systems of bafflesor dividers between components to direct the blast from one componentaway from other components. These systems, however, add cost andcomplexity, and may still create hazardous conditions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an embodiment of a venting system for an electricalswitching component according to the inventive principles of this patentdisclosure.

FIG. 2A is a front view of another embodiment of a venting systemaccording to the inventive principles of this patent disclosure.

FIG. 2B is a cross section taken through line AA of the embodiment ofFIG. 2A.

FIG. 3 illustrates an embodiment of a relay according to some inventiveprinciples of this patent disclosure.

FIG. 4 illustrates an embodiment of a relay card according to someinventive principles of this patent disclosure.

FIG. 5 is a cross-sectional view illustrating another embodiment of aventing system according to some inventive principles of this patentdisclosure.

FIG. 6 is a cross-sectional view illustrating another embodiment of aventing system according to some inventive principles of this patentdisclosure.

FIG. 7 is a cross-sectional view illustrating another embodiment of anelectrical switching component according to some inventive principles ofthis patent disclosure.

FIG. 8 is a partially exploded perspective view illustrating anotherembodiment of a venting system according to some inventive principles ofthis patent disclosure.

FIG. 9 is a perspective view showing the opposite side of the embodimentof FIG. 8.

FIG. 10 is a perspective view illustrating an electrical switchingdevice according to some inventive principles of this patent disclosure.

FIG. 11 is a cutaway view illustrating a duct according to someinventive principles of this patent disclosure.

FIG. 12 is a cross-sectional view illustrating an example of aninterface of the electrical switching device and case of FIG. 11.

FIG. 13 is an exploded cutaway view of the embodiment of FIG. 11.

FIG. 14 is a cross-sectional view illustrating an example of aninterface of a wall of the case and a wall of the electrical switchingdevice.

FIG. 15 is a cutaway view illustrating a bulkhead according to someinventive principles of this patent disclosure.

FIG. 16 is an exploded cutaway view of the embodiment of FIG. 15 from adifferent angle.

FIG. 17 is a cutaway view illustrating a circuit board in the assemblyof FIG. 16 according to some inventive principles of this patentdisclosure.

FIG. 18 is a cutaway view illustrating a circuit board according to someinventive principles of this patent disclosure.

FIG. 19 is the cutaway view of FIG. 17 without the circuit board.

FIG. 20 is a cutaway view illustrating a bulkhead and terminalsaccording to some inventive principles of this patent disclosure.

FIG. 21 is the cutaway view of FIG. 20 rotated to illustrate a ventaccording to some inventive principles of this patent disclosure.

FIG. 22 is a cross-sectional view illustrating a second chamberaccording to some inventive principles of this patent disclosure.

FIG. 23 is a cross-sectional view illustrating a wall of the secondchamber of FIG. 22 according to some inventive principles of this patentdisclosure.

FIG. 24 is a block diagram illustrating an example of guiding a blastaccording to some inventive principles of this patent disclosure.

FIG. 25 is a block diagram illustrating various zones according to someinventive principles of this patent disclosure.

FIG. 26 is a block diagram illustrating additional zones of the circuitboard of FIG. 25 according to some inventive principles of this patentdisclosure.

FIG. 27 is a perspective view illustrating an electrical switchingcomponent according to some inventive principles of this patentdisclosure.

FIG. 28 is a cutaway view illustrating an actuator according to someinventive principles of this patent disclosure.

FIG. 29 is a perspective view illustrating a case according to someinventive principles of this patent disclosure.

FIG. 30 is a side view illustrating the protrusion and mounting ear ofFIG. 29.

FIG. 31 is a plan view of an example of a mounting site for the assemblyof FIG. 29.

DETAILED DESCRIPTION

FIG. 1 illustrates an embodiment of a venting system for an electricalswitching component according to the inventive principles of this patentdisclosure. The embodiment of FIG. 1 includes an electrical switchingcomponent 10 having an electrical switching device (not shown)substantially encapsulated in a case 12. The case has a mounting portion14, which in this example is the bottom of the case 12. The mountingportion includes a vent 16 to enable gases and other material from ablast to escape from within the case. The embodiment of FIG. 1 alsoincludes a chassis 18 having a mounting site 20 where the electricalswitching device 10 is mounted to the chassis. The mounting site 20includes a passage 22 to enable the blast from vent 16 to flow from thecase through the chassis and into a blast diverting space 24.

FIG. 1 shows the electrical switching component 10 elevated above thechassis 18 so as not to obscure the details of the mounting site 20.When fully assembled, however, the electrical mounting portion 14 ofswitching component 10 is mounted to the mounting site 20 of the chassis18 so the vent 16 is generally aligned with the passage 22.

The electrical switching device contained in the case is not shown inFIG. 1 so as not to obscure the mounting portion 14 or vent 16. Theelectrical switching device may be a relay, a circuit breaker, amanually actuated switch, a dimmer, or any other type of device orcombination of devices that controls current to a load and which, inresponse to electrical stress such as a short circuit, over currentcondition, etc., or during normal operation, may produce a blast ofgases, molten metal or any other matter that may damage or interferewith the operation of the device if not vented out of the case. A blastneed not necessarily be a high pressure event, but may be, for example,a puff of ionized air generated by an arc caused by opening a switch onan inductive load.

The case 12 may be of any suitable size, shape, material, etc., forenclosing the specific type of electrical switching device. Someexamples of suitable materials include various plastics, composites,glasses, metals, etc. commonly used for encapsulating relays, circuitbreakers, switches, etc. The case 12 need not completely encapsulate theelectrical switching device. For example, the case may includeloose-fitting openings around electrical terminals that pass through thecase, or there may be small gaps where different portions of the caseare joined, or there may be imperfectly fit openings for access topotentiometers, dip switches and the like. Relatively small amounts ofgas or other matter may escape from these openings without defeating thepurpose of the vent 16.

The vent 16 may have any suitable form to vent gases or other materialfrom the case. Some examples include a simple circular hole, acombination of holes to form a baffle, a pressure relief valve set toopen only when the inside of the case reaches a certain internalpressure and/or temperature, a relatively thin or weak portion of thecase that ruptures under pressure or high heat, an elastomeric materialthat opens to vent, but then recloses after venting, etc.

The mounting portion 14 in the embodiment of FIG. 1 is shown as a flatbottom portion of the case 12 to enable the case to be attached to theflat mounting site 20 on chassis 18, but countless variations arecontemplated by the inventive principles of this patent disclosure. Forexample, in some embodiments, the mounting portion may be molded with aprofile to fit in or on a rail or track such as a standard DIN rail. Inother embodiments, the mounting portion may be shaped to plug into arelay socket. In an embodiment for a snap-in type circuit breaker, themounting portion may include the flat bottom of the circuit breaker casewhich is bounded at one end by a hook to engage the panel and at theother end by the plug-in terminal to engage the power distribution bus.

The manner in which the electrical switching component 10 is attached tothe chassis 18 is not limited to any particular technique and may dependon the configuration of the chassis 18 and/or the mounting portion 14 ofthe case 12. In an embodiment having two flat mating surfaces as shownin FIG. 1, any type of fasteners such as screws, rivets, clips, adhesiveetc. may be used. Either or both surfaces may have interlocking tabs,slots, recesses, protrusions, etc. In embodiments that utilize plug-insockets, the case may be held to the chassis by the force of matingcontacts and or tabs in the case. These forces may be supplemented orreplaced by hold-down clips or other fasteners. As another example, inembodiments that utilize mounting rails or tracks, the mounting portion14 of the case 12 may simply slide into or on the track or rail.

The chassis 18 and mounting site are not limited to any particularconfigurations, although some specific examples are described below. Inthe embodiment of FIG. 1, the chassis 18 is shown as a flat mountingplate that can be fabricated from metal or any other suitable material,and the mounting site 20 is simply a portion of the plate matching thefootprint of the case 12. In some other embodiments, the chassis may bein the form of a rail or a track in which any portion of the rail ortrack may be designated as a mounting site. In other embodiments, thechassis may be a socket having a mounting site that includes receptaclesfor electrical terminals and/or tabs on the mounting portion of thecase. In yet other embodiments, a printed circuit board may serve as thechassis with a mounting site that includes drilled holes, plated holes,etc. to receive the electrical switching component in the form of aboard mount relay, circuit breaker, etc. The chassis may be afree-standing chassis, or it may be mounted in, or integral with, anenclosure.

The passage 22 is shown as a simple circular hole in the embodiment ofFIG. 1, but the inventive principles contemplate many different forms.The passage may include multiple holes, channels, tubes, valves, etc. todirect the blast from the vent 16 to the blast diverting space 24. Aswith the vent 12, the passage 22 may be implemented as a relatively weakor thin portion of the chassis that ruptures under pressure or heat.

The blast diverting space 24 may be any suitable open or enclosed space.For example, it may be specifically designed to receive the blast, or itmay utilize an existing space in the chassis or an enclosure in whichthe chassis is mounted. The blast diverting space may be empty, or itmay be fully or partially filled with material to absorb, diffuse, cool,redirect, or otherwise process the blast.

FIGS. 2A and 2B (which may be referred to collectively as FIG. 2)illustrate another embodiment of a venting system according to theinventive principles of this patent disclosure. The embodiment of FIG. 2is directed to a relay control panel that is housed in a sheet metalenclosure 26. The electrical components are attached to a mounting plate28 which, as best seen in FIG. 2B, is spaced apart from the back wall 30of the enclosure 26 to form a space 32 which is utilized as a blastchamber as described below. The mounting plate 28 may be positionedrelative to the back wall using spacers, folded sheet metal, or anyother suitable technique.

Referring to FIG. 2A, the relay control panel may include any number ofrelays 34 which, in this example, are arranged in two rows on eitherside of low-voltage control circuitry 36. The low-voltage controlcircuitry may include a printed circuit board having one or moremicroprocessors, communication interfaces, timing circuits, interfacecircuitry for photo sensors, occupancy sensors and the like, as well ascircuitry to drive the coils of relays 34. High voltage wiring areas 38on either side of the enclosure 26 provide space for the connection ofline and load wires to the relay contact terminals. Though not shown,the enclosure may include a front panel to fully enclose the panel.

In the example embodiment of FIG. 2, the relays may have molded plasticcases with mounting portions implemented as flat bottom flanges thatmount directly to designated sites on the mounting plate 28 using anysuitable attachment technique. High-voltage connections may be made tothe relay contacts through spade-lug connectors or screw terminals onthe tops of the relays, while low voltage connections may be made to therelay coils through similar terminals on the tops of the relays.

In other embodiments, the relays may be attached in the form of relaycards having one or more relays mounted on a printed circuit board alongwith terminal blocks and other support circuitry. Each relay card mayhave a terminal header to couple the card to corresponding terminals ofthe low voltage control circuitry 36. The relay card may also beattached to the mounting panel with spacers, stand-offs, a sheet ofinsulated material, etc.

In the embodiment shown in FIG. 2B, each relay has a vent hole 40 in thebottom of its case that aligns with a corresponding hole 42 in themounting plate 28. In an embodiment having relay cards, each printedcircuit board may have a corresponding hole that aligns with both of theholes 40 and 42. Depending on the manner in which the printed circuitboard is attached to the mounting plate, i.e., if the card is spacedapart from the plate, a tube or other apparatus may be included todirect the blast from the holes in the relay and printed circuit boardto the hole in the mounting plate 28.

As best seen in FIG. 2B, any blast from one of the relays 34 is directedinto a blast chamber 32 formed between the mounting plate 28 and theback wall 30 of the enclosure, as well as a portion of the top wall 44and bottom wall 46 and the side walls 48 and 50 of the enclosure. A vent52 is located at the lower end of the mounting plate 28 and opens theblast chamber into the main volume 54 of the enclosure. Upon releasefrom the vent hole 40, gases and/or other matter in a blast from relay34 is dispersed throughout the blast chamber 32 and may eventuallytravel downward to vent 52. If and when the blast makes its way throughvent 52 and into the main volume 54 of the enclosure 28, it may havedissipated enough to prevent damage or interfere with the operation ofother components located within the enclosure. For example, hot exhaustgases may have cooled, ionized air may have become de-ionized, andmolten metal may have solidified, clung to the back wall of theenclosure, or fallen to the bottom of the blast chamber.

The blast chamber 32 may be empty, or it may be fully or partiallyfilled with a material such as loose flame-resistant fiberglassinsulation batting to further contain the blast.

The embodiment of FIG. 2 may provide several benefits depending on theimplementation. For example, the system may require few, if anyadditional components. Electrical enclosures typically include mountingplates that are attached to the back wall of the enclosure with spacersor standoffs. A mounting plate is typically fabricated by a stampingoperation in which the plate is cut to size and any necessary holespunched in one stamping operation. The additional holes for the ventsmay be fabricated in the same stamping operation. Likewise, the ventholes for the relays may be formed in the same molding operation used tocreate the relay case. Other than providing electrical isolation betweencomponents on the mounting plate and the back wall of the enclosure, thespace between the plate and the enclosure may essentially be wastedspace. Thus, at low additional cost, and perhaps even no additionalcost, the embodiment of FIG. 2 may provide effective blast containmentby modifying existing components and utilizing previously wastedportions of an electrical enclosure to solve a problem that has troubledpanel designers for years.

FIG. 3 illustrates an embodiment of a relay 56 according to someinventive principles of this patent disclosure. In the embodiment ofFIG. 3, a relay circuit (not shown) is encapsulated in a molded plasticcase 58 having a flat mounting portion 60. The flat mounting portionincludes tabs 62 a-62 d which form an enlarged flange at the bottom ofthe relay for attachment to a generally flat mounting site on a chassis.Slots 64 a, 64 b are formed between the tabs on either side of theflange to accommodate screws or other fasteners to attach the relay tothe chassis. Electrical connections are made to the relay throughterminals 66 a, 66 b which protrude through the top of the case 58. Avent hole 68 enables gases or other material to escape from within thecase 58. The vent hole 68 may be sized and located to align with acorresponding passage in the mounting site of the chassis. Although notlimited to any particular application, the embodiment of FIG. 3 may besuited for use in the embodiment of the relay panel of FIG. 2.

FIG. 4 illustrates an embodiment of a relay card according to someinventive principles of this patent disclosure. The relay card 70 ofFIG. 4 includes a relay 72 having a case 74 with a mounting portion 76,which in this example is the bottom of the case 74. The mounting portionincludes a vent 78 to enable gases and other material from a blast toescape from within the case. The relay 72 is attached to PC board 80 ata mounting site 82 which includes an additional passage or vent 84 toenable the blast to pass through the printed circuit board. A terminalheader 86 on the bottom of the PC board engages terminal pins on acontrol PC board to couple the relay coil and other circuitry on therelay board to low-voltage control circuitry on a control PC board, orto other control circuitry. A terminal block 88 enables high-voltagewiring to be connected to the contacts of the relay 72 through traces onthe PC board. Connections to the relay are through terminals (notvisible in this view) on the bottom of the case 74 which may be solderedto contacts, plated holes, etc., on the PC board.

The relay card 70 of FIG. 4 maybe mechanically supported at one end bythe terminal header 86 and at the other end by a standoff attached to amounting hole 90. If the terminal card of FIG. 4 is used in a systemsuch as the relay panel shown in FIG. 2, the blast from vents 78 and 84may be further directed through a corresponding hole 42 in the mountingplate 28. A tube or other blast directing device may be included betweenthe PC board and the mounting plate to form a continuous passage betweenvents 78 and 84 and hole 42 in the mounting plate 28.

FIG. 5 illustrates another embodiment of a venting system according tosome inventive principles of this patent disclosure. The embodiment ofFIG. 5 includes a relay 92 similar to the relay 72 of FIG. 4. Ratherthan being mounted to a PC board, however, the relay 92 is mounted in aplug-in relay socket 94. Though not shown in FIG. 5, electrical andmechanical connections are made through terminal pins or spades thatprotrude from the bottom mounting portion 96 of the relay 92 and extendthrough openings in a mounting site 98 of the socket to engagereceptacles in the socket. The socket 94 also includes a bottom mountingportion 100 that mounts to a mounting site 102 on a plate 104 or otheradditional chassis.

In the embodiment of FIG. 5, the socket 94 is formed with athrough-passage 106 to connect vent 108 in the bottom of the relay 92with a passage 110 in the plate 104. This provides a continuous passageto channel a blast from the relay through the socket and plate and intoa blast chamber 112. In an alternative embodiment, the socket itself mayinclude a blast chamber, in which case, the bottom of the socket may beclosed, or have a reduced aperture to enable only a portion of the blastto pass through the socket and plate.

FIG. 6 illustrates another embodiment of a venting system according tosome inventive principles of this patent disclosure. The embodiment ofFIG. 6 includes a mounting track or rail 114 such as a standard DINmounting rail. An electrical switching component 116 includes a case 118having a mounting portion 120 with a vent 122. The case is secured tothe rail 114 by rail-engaging members 124 a, 124 b. The mounting site issimply the portion of the rail on which the case is mounted. In thisembodiment, the rail may serve as a blast chamber, either alone, or bydirecting the blast to one or more additional blast diverting spaces.Thus, the interior cavity of the rail may be filled with blast-absorbingmaterial.

FIG. 7 is a cross-sectional view illustrating another embodiment of anelectrical switching component according to some inventive principles ofthis patent disclosure. In the embodiment of FIG. 7, a relay is housedin a case 126 having at least two chambers. A first chamber 128 containsa pair of contacts 132 a,132 b, or other switching element, electricallyconnected to terminals 134 a,134 b that extend through the case 126. Avent 142 enables a blast from the contacts, for example from an overloador short circuit condition, to escape from the first chamber. The firstchamber may include other openings, provided a substantial portion of ablast is directed through vent 142. In some embodiments, the portion ofthe case having the vent 142 may be a mounting portion, which may alsoinclude the terminals 134 a, 134 b.

A second chamber 130 includes a solenoid 136 or other actuating deviceto actuate the contacts using a plunger 138 that passes through achamber wall that separates the first and second chambers. The secondchamber 130 also includes electronics 140 to control the operation ofthe relay and communicate with external components such as a controller.

Placing the contacts 132 a, 132 b in a separate chamber may protect thecomponents in the second chamber from a blast from the contacts. Thesecond chamber need not be totally enclosed, but may simply be separatedenough from the first chamber to substantially protect components in thesecond chamber from a blast in the first chamber.

Countless variations of this embodiment are possible according to someof the inventive principles of this patent disclosure. In the example ofFIG. 7, there are two chambers, but other configurations havingdifferent numbers of chambers are contemplated. Some variations mayinclude locating the relay coil in the first chamber or a third chamber.In other embodiments, additional sets of contacts may be located in thefirst chamber, or the additional contacts may be located in a thirdchamber, fourth chamber, etc., to prevent a blast from one set ofcontacts from interfering with the operation of the other contacts. Theadditional chambers may have additional vents which may be located inthe same mounting portion as the first vent, in a different mountingportion of the case, or in a non-mounting portion of the case.

FIG. 8 is a partially exploded perspective view illustrating anembodiment of a relay assembly having a venting system according to someinventive principles of this patent disclosure. The embodiment of FIG. 8illustrates a two-pole assembly, meaning that two different relays forswitching two different circuits are included in one case. The caseincludes two side shells 144 a and 144 b, each of which houses one ofthe relays. In this view, only the left-side relay 146 a is visible. Abulkhead 148 divides the entire case in half so that a blast on one sidedoes not interfere with the operation of the circuitry on the otherside. The case also includes a base plate 150 to mount the relayassembly to a mounting site on a plate, channel, or other suitableapparatus.

Connections to the contacts of the left-side relay 146 a are throughconductors 152 a and 154 a. External wires may be connected to theconductors by screw terminals (not shown) attached to the conductors.Apertures 156 a and 158 a allow the wires to be inserted into theterminals, while apertures 160 a and 162 a provide screwdriver access tothe terminals. Connections to the relay solenoid and/or controlelectronics may be made through header pins, terminal blocks, wire leadsor any other suitable arrangement. In the example of FIG. 8, the relay146 a is mounted to a printed circuit board 164 which includes headerpins (not visible in this view) to provide connections through the caseto the relay solenoid and/or control electronics on the circuit board. Aslider plate 166 moves manual override actuators simultaneously on bothrelays in response to motion of a manual actuator 168 which protrudesthrough an opening in the case.

In the event of a blast from relay 146 a, another bulkhead 170 preventsthe blast from exiting the terminal apertures 156 a-162 a (which maydamage the external wires) and instead directs the blast through a vent172 a in the base plate 150. Another vent 172 b (not visible in thisview) is arranged in a similar location on the other side of the baseplate to vent a blast from the relay 146 b on the other side of thecase.

Relay 146 a may be an open frame device, or it may be contained withinanother (inner) case as shown here. The inner case may have a singlechamber, or it may have multiple chambers as described above in thecontext of FIG. 7. The inner case may be designed to rupture in theevent of a blast, in which case the gases and/or other material from theblast flow through the open spaces within the outer case 144 a, 144 b,150 until they are directed to the vent 172 a. In some embodiments,additional bulkheads, passages, baffles, etc. may be arranged within theouter case to channel the blast to the vent. Alternatively, the innercase may be designed to expel a blast in a more controlled manner. Forexample, the inner case may include a vent in a mounting portion, or anyother portion, which may be oriented to direct a blast in the generaldirection of the vent 172 a, either directly through any open space inthe outer case, or through a system of additional bulkheads, passages,baffles, etc.

FIG. 9 is a perspective view showing the opposite side of the embodimentof FIG. 8. In the view of FIG. 9, both of vents 172 a and 172 b arevisible in the base plate 150, and both case shells 144 a and 144 b areshown in their assembled positions. A right angle header 174 is shown inthe position it is in when the header pins for the solenoid/controlconnections are fully engaged with the header. The right angle terminalsextending from the header 174 may be soldered to a circuit board (notshown) on which control circuitry is located. For example, controlcircuitry 36 shown in FIG. 2A may be interfaced to the embodiment ofFIG. 9 through header 174. Another connector 176 may be included toprovide additional or alternative mechanical and/or electricalconnections to the relay assembly.

In the embodiment of FIG. 9, the base plate 150 includes mounting ears178 and 180 which may pass through apertures in a mounting plate andengage the plate to secure the relay assembly to a mounting site on theplate when the relay assembly is slid in the direction of arrow A. Thissliding action may also cause the terminal pins to engage in header 174,and may additionally cause connector 176 to engage the case of the relayassembly. The vents 172 a and 172 b are located relative to mounting ear178 such that, after the mounting ear passes through an aperture on themounting plate and the relay assembly is slid into position in thedirection of arrow A, the aperture is then positioned over the vents toenable the vents to communicate with the space on the other side of themounting plate. Thus, the one aperture in the mounting plate operatessynergistically as both a passage to vent a blast, and an aperture toengage the mounting ear 178.

Although the example embodiment of FIGS. 8 and 9 is shown as a two-polerelay assembly, other embodiments may be realized with relays, circuitbreakers, or other switching devices, and with any number of poles,e.g., single pole, three-pole, etc. Moreover, any number of switchstates or positions may be used, for example, single throw, doublethrow, etc.

FIG. 10 is a perspective view illustrating an electrical switchingdevice according to some inventive principles of this patent disclosure.In this embodiment, the electrical switching device 200 includes a case202, contacts 204 and 206, a manual actuator 210, and a solenoid 212. Awall 216 within the electrical switching device substantially separatesthe contacts 204 and 206 within the case 202 from the manual actuator210 and the solenoid 212. The contacts 204 and 206 are coupled toterminals 208 and 209.

Although the electrical switching device 200 is illustrated apparentlyas a cutaway view, in an embodiment, the electrical switching device 200can have an open side. For example, the case 202 can be configured toinclude less than all sides to encapsulate the internal components. Thatis, the electrical switching device 200 can be manufactured with thecontacts 204 and 206, solenoid 212, or the like within the case 202exposed. In another embodiment, the electrical switching device 200 canbe configured with a wall enclosing the contacts 204 and 206, solenoid212, or the like. The electrical switching device 200 can be configuredthat such a wall is removable. For example, the electrical switchingdevice 200 can be an off-the-shelf component. In particular, theelectrical switching device can be an off the shelf componentsubstantially lacking in structures to guide a blast. That is, a blastcould exit from the case 202 of such an off-the-shelf electricalswitching device 200 in an undetermined location on the case 202.However, by removing a lid, wall, side, or the like of such anelectrical switching device 200, a blast can be guided as will bedescribed in further detail below. Regardless, the electrical switchingdevice 200 includes an opening in the case 202 that is configured toexpose the contacts 204 and 206.

Although an opening in the case 202 has been illustrated as includingsubstantially all of one side of the electrical switching device 200,the opening can include more or less of the case 202. For example, in anembodiment, the case 202 can include an opening that only exposes thecontacts 204 and 206 within the case. In other words, the manualactuator 210, the solenoid 212, or the like within the case 202 may notbe exposed through the opening. In another embodiment, multiple sides ofthe electrical switching device 200 can expose the internal components.

Although a particular type of electrical switching device has beendescribed, namely an electrical switching device 200 with a solenoid 212actuator, any actuator can be used. In addition, the electricalswitching device 200 can be any switching device as described above.

FIG. 11 is a cutaway view illustrating a duct according to someinventive principles of this patent disclosure. In this embodiment, acase can be arranged to substantially encapsulate the electricalswitching device 200. A side 234 of the case is illustrated. Theelectrical switching device 200 is disposed in contact with the side.

In the following description, various portions of an electricalswitching device assembly will be described. However, portions that mayhave been previously described or portions that will be described latermay or may not be illustrated. The illustrations may omit some portionsfor the sake of clarity.

The side 234 includes at least one duct 230. A duct 230 includes one ormore structures that form an opening. The duct 230 is disposed adjacentto the electrical switching device 200. In particular, the duct 230 isdisposed adjacent to the opening in the electrical switching device 200.Accordingly, as the opening is disposed to expose the contacts 204 and206 of the electrical switching device 200, any blast from the contacts204 and 206 can enter the duct 230.

In this embodiment, a rib 232 can be disposed in the ducts. The rib 232can be disposed in the duct 230 such that the duct 230 has additionalstructural support. For example, the rib 232 can increase a stiffness ofthe side 234 in the duct 230. In an embodiment, the duct 230 can beformed from a recessed region of the side 234. The recessed region canbe strengthened by ribs 232. Although one rib 232 has been described, inan embodiment, multiple ribs 232 can be disposed in the duct 230 asdesired.

In another embodiment, the rib 232 can be configured to contact the case202 of the electrical switching device 200. As a result, the rib 232 canprovide an amount of support to the case 202. Moreover, in anembodiment, the rib 232 can but need not be aligned substantiallyparallel to an axis of the case 202. For example, the rib 232 can bedisposed at an angle, such as at an angle directed towards a vent. Thus,the rib 232 can be configured to guide a blast from the electricalswitching device 200.

In another embodiment, the side 234 can include a bulkhead 233. Thebulkhead 233 is disposed extending from a top 235 of the side 234 to thecase 202. As described above, the duct 230 can guide a blast from theelectrical switching device 200. However, once the blast exits theelectrical switching device 200, the blast can expand through anyavailable opening. The bulkhead 233 can be configured to substantiallyisolate other electrical circuitry from the blast. That is, the bulkhead233 can guide the blast away from travelling around the case 202.

FIG. 12 is a cross-sectional view illustrating an example of aninterface of the electrical switching device and case of FIG. 11 alongcross-section 231. The case 202 of the electrical switching device 200is in contact with the side 234 of the case. Where the case 202 contactsthe side 234, the side 234 can include walls 236 and 238. The walls 236and 238 can be disposed to contact a perimeter of the case 202. Althoughwalls of the side 234 have been described, in an embodiment, theperimeter of the case 202 can contact the surface of the side 234. Thatis, the side 234 need not have distinguishable walls to contact the case202. However, the case 202 and the side 234 can still be in contact toaid in guiding a blast.

Accordingly, the contact of the case 202 and the side 234 forms the duct230. Gasses, particles, or the like from a blast can be exhaustedthrough the duct 230. In particular, in an embodiment, the case 202 ofthe electrical switching device 200 can form an expansion chambercoupled to the duct 230. As will be described in further detail below,the duct 230 can open on to such an expansion chamber. The blast can beguided into the expansion chamber where the gases can expand and cool.

FIG. 13 is an exploded cutaway view of the embodiment of FIG. 11. Inthis view, the electrical switching device 200 is illustrated as offsetfrom the side 234 to expose the wall 240. The wall 240 of the side 234can be disposed within the case 202 of the electrical switching device200.

That is, in an embodiment, the wall 240 can be configured to extend intothe case 202 of the electrical switching device. The wall 240 can beconfigured to be disposed adjacent to the wall 216 of the case 202.Accordingly, the wall 216 of the case and the wall 240 of the side 234can function as a bulkhead to contain a blast from the contacts 204 and206.

Additional walls can also contact the case 202. For example, the walls236, 238, and 246 of the side 234 and the corresponding perimeter of thecase 202 of the electrical switching device 200 form additional walls.The case 202 can provide additional walls. Such walls can substantiallycontain a blast.

However, because of the interface between the case 202 and the duct 230,an opening remains to guide the blast from the chamber 244. As a result,the blast can be guided away from the electrical switching device 200.

FIG. 14 is a cross-sectional view illustrating an example of aninterface of a wall of the case and a wall of the electrical switchingdevice. As described above, a wall 216 can separate the contacts 204 and206 from other components of the electrical switching device 200, suchas the solenoid 212. The wall 240 of the side 234 extends into theelectrical switching device 200. In this embodiment, the wall 240partially extends into the electrical switching device 200. However, inother embodiments, the wall 240 can fully extend to the opposite side ofthe electrical switching device 200. In another embodiment the wall 240can form a butt joint.

That is, the wall 240 of the side 234 and the wall 216 of the electricalswitching device 200 form a wall of a chamber 244. Accordingly, a blastfrom contacts 204 and 206 can be guided substantially in a desireddirection. Accordingly, any blast from the contacts 204 and 206 can besubstantially prevented from traveling towards the solenoid 212 or otherelectronics. The blast can be guided through the duct 230.

In an embodiment, the duct 230 can be the only opening exposing thechamber 244 to a region external to the electrical switching device 200.For example, the contact of the walls, the case 202, and the like can besealed together. Adhesives, welding, gaskets, or the like can seal thesurfaces together. As a result, the only route for expanding gas andparticles from the blast is through the duct 230.

In another embodiment, the duct 230 can be sized such that a majority ofthe blast is directed through the duct 230. For example, there can besome opening between the wall 216 of the electrical switching device 200and the wall 240 of the side 234. Other interfaces, such as theinterface of the walls 236 and 238 to the perimeter of the electricalswitching device 200 can also have similar gaps, openings, or the like.As a result, a portion of the blast can escape beyond the junction ofthe walls.

However, the duct 230 can be sized such that a cross-sectional area ofan opening created in the duct 230 between the side 234 and theelectrical switching device 200 can be greater than a combination ofsimilar cross-sectional areas of the gaps, openings, or the likedescribed above. As a result, even though it is possible for the blastto escape through the other openings, a majority of the blast can escapethrough the duct 230.

As illustrated in FIG. 14, the wall 240 can be a planar wall. Asillustrated in FIG. 13, the wall 240 can include multiple walls.Accordingly, the wall 240 can take any variety of configurations. Thatis, the wall 240 can be disposed on the solenoid 212 side of the wall216. In another embodiment, the wall can straddle the wall 216. Inanother embodiment, the wall 240 can be disposed on the contact 206 sideof the wall 216.

FIG. 15 is an exploded cutaway view illustrating a bulkhead according tosome inventive principles of this patent disclosure. FIG. 16 is anexploded cutaway view of the embodiment of FIG. 16 from a differentangle. Referring to FIGS. 15 and 16, in an embodiment, a first bulkhead258 can extend between an electrical switching device 200 and a secondbulkhead 252.

In this embodiment, the first bulkhead 258 is part of a center bulkhead254 dividing the electrical switching component. When the centerbulkhead 254 is assembled with the side 234, the bulkhead 258 isdisposed between the electrical switching device 200 and the secondbulkhead 252.

In an embodiment, the second bulkhead 252 is a circuit board. However,the second bulkhead 252 need not be a circuit board. For example, in anembodiment, the second bulkhead 252 can be a bottom 250 of theelectrical switching component, the side 234, or the like. Thus, thebulkhead 258 can extend from the electrical switching device 200 to thebottom 250 of the electrical switching component. In another embodiment,the second bulkhead 252 can be another internal structure of theelectrical switching component. Similar to the bulkhead 233 describedabove, the bulkhead 258 can substantially isolate other electricalcomponents from the blast by guiding the blast away from the side of thecase 202.

FIG. 17 is a cutaway view illustrating a circuit board in the assemblyof FIG. 16 according to some inventive principles of this patentdisclosure. In this view, the center bulkhead 254 is assembled with theside 234. The center bulkhead 254 can include a duct 230, a wall 240,and the like similar to the side 234. Accordingly, a second electricalswitching device (not illustrated) similar to the electrical switchingdevice 200 described above can be assembled with the center bulkhead. Abulkhead 256 can extend from the electrical switching device to thebulkhead 252.

In addition to guiding the blast, the various bulkheads can isolateother electrical circuitry from the blast. As described above, a blastcan travel through duct 230. The blast can expand towards the circuitboard 252. The blast can be blocked by the circuit board 252.Accordingly, electrical components, and in particular, electricalcomponents that are electrically coupled to lower voltage circuitry, canbe protected from the blast.

Although the bulkhead 256 has been illustrated as substantially in linewith the wall 240, the bulkhead 256 can be disposed in other locations.For example, the bulkhead 256 can be disposed further away from theducts 230. Additional walls such as the wall 242 can contact theperimeter of the case 202 of the electrical switching device 200.Accordingly, other components including the components of the electricalswitching device 200 can be substantially isolated from the blast.

Although the duct 230 has been illustrated as disposed on the centerbulkhead 254, the duct 230 can be disposed in other locations. In anembodiment, the duct 230 can be disposed on another side (notillustrated) of the electrical switching component opposite the side234. In another embodiment, the ducts for multiple electrical switchingdevices 200 can be disposed on the center bulkhead 254. The openings ofthe electrical switching devices 200 can be disposed to open on to theduct 230, regardless of the particular location.

FIG. 18 is a cutaway view illustrating a circuit board according to someinventive principles of this patent disclosure. In this embodiment, thecircuit board 252 is mounted to the side 234 and the bottom 250. Thecircuit board 252 can be similarly mounted on another side of the case(not illustrated). The circuit board 252 is supported by stand-offs 270and 272. The stand-offs 270 and 272 can be configured to offset thecircuit board 252 from the bottom 250. As a result, circuitry can bedisposed on side 255 of the circuit board 252.

In addition to supporting the circuit board 252, the stand-off 270 cansubstantially isolate the opposite side 255 of the circuit board 252.For example, the blast can be directed along the circuit board 252. Thestand-off 270 can also be configured to direct such a blast away fromthe opposite side 255 of the circuit board 252.

FIG. 19 is the cutaway view of FIG. 18 without the circuit board.Supports 280 and 282 can be configured to support an edge of the circuitboard 252. For example, the circuit board 252 can be disposed betweenthe supports 280 and 282.

The supports 280 and 282 can extend along a length of the circuit board252. In particular, in an embodiment, the support 280 can extend along alength of the circuit board 252. Accordingly, when a blast increases thepressure on the circuit board 252, the circuit board 252 can be pressedon to the support 280. Thus, the blast can be substantially preventedfrom escaping around an edge of the circuit board extending along thelength.

The support 280 can, but need not extend along the entire length of thecircuit board 252. For example, the support can extend only along alength of the circuit board 252 where the circuit board 252 mayencounter a blast. Similarly, the support 282 can, but need not extendalong an entire length of the circuit board 252. For example, thesupport 282 can include periodically spaced supports along the edge.Although the support 280 has been illustrated as continuous along alength of the circuit board 252, the support 280 can includeperiodically spaced structures.

The supports 280 and 282 have been illustrated for an example. Othersupports can be included on another side of the case, a center bulkhead254, or the like. Accordingly, along a perimeter of the circuit board252, the edges of the circuit board 252 can be substantially sealed.However, in an embodiment, the edges of the circuit board can, but neednot be substantially sealed beyond a bulkhead, such as bulkhead 256 or258. That is, if the blast is substantially isolated from a region ofthe circuit board 252, the edges in that region need not besubstantially sealed.

Moreover, although the supports 280 and 282 have been illustrated asprotrusions, the supports 280 and 282 can take different forms. Forexample, the supports 280 and 282 can include a slot, recessed region ofthe side 234, or the like configured to receive an edge of the circuitboard 252. Any combination of such protrusions and recessed regions canbe used.

FIG. 20 is a cutaway view illustrating a bulkhead and terminalsaccording to some inventive principles of this patent disclosure. Inthis embodiment, a second electrical switching device 200 is illustratedas assembled on the center bulkhead 254. The contacts of the electricalswitching device 200 are coupled to conductors 294. The conductors 294are coupled to corresponding terminals 290. The terminals 290 can beconfigured to be coupled to wiring 292.

Although the terminals 290 have been illustrated as screw terminals, theterminals 290 can have a variety of configurations. For example, theterminals 290 can be quick connect terminals, connectors, or the like.

A blast from the electrical switching device 200 can travel through thechamber including the conductors 294. However, a bulkhead 296 can bedisposed between the electrical switching device 200 and the terminals290. The conductors 294 can be disposed to extend through the bulkheadwhere the bulkhead 296 can be configured to substantially isolate theterminals 290 from a blast.

As illustrated in FIG. 20, the bulkhead 296 is part of the centerbulkhead 254. However, a gap 295 can be present in the bulkhead 296 toallow for placement of the conductors 294. The gap 295 can besubstantially filled by a corresponding structure on another side (notillustrated) of the electrical switching component. Accordingly,although the bulkhead 296 has been described as substantially isolatingthe terminals 290 from a blast, the isolation can include a contributionfrom the additional structure of the other side. Moreover, although thebulkhead 296 has been illustrated as an internal bulkhead, the bulkhead296 can be formed from a side of the case, such as side 234. That is, inan embodiment, the bulkhead 296 can be a wall of the case.

FIG. 21 is the cutaway view of FIG. 20 rotated to illustrate a ventaccording to some inventive principles of this patent disclosure. Asdescribed above, a vent 300 can be disposed in the case to allow a blastto vent to outside of the case. In this embodiment, the vent 300 isdisposed between the electrical switching device 200 and the bulkhead296. However, in other embodiments, the vent 300 can be disposedanywhere such that there is a substantially continuous path between theelectrical switching device 200 and the vent.

Accordingly, a blast can occur in the electrical switching device 200.The blast can be guided through the ducts 230. The ducts 230 can ventinto the chamber defined by the center bulkhead 254, the circuit board252, the bulkhead 256, the bulkhead 296, and the other side (notillustrated). As the chamber is larger than the chamber 244 of theelectrical switching device 200, the blast can expand, reducing thetemperature and pressure. The gap between the stand-off 270 and thebulkhead 296 directs the blast towards the vent 300 and towards anexterior of the electrical switching component.

Similar to the size of the duct relative to the size of any openingcreated by the junction of the case 202 of the electrical switchingdevice 200 and the side 234, the size of the vent 300 can be selectedsuch that a cross-sectional opening of the vent 300 is larger than acombination of other gaps, openings, or the like between the varioussides, circuit board, bulkheads, and the like guiding the blast.Accordingly, a substantial amount of the blast can be guided out of thevent 300.

In an embodiment, the electrical switching component can includemultiple bulkheads disposed between the electrical switching device 200and the terminals 290. As illustrated in FIG. 21, the conductor 294extends through bulkhead 297. In this embodiment, only one of theconductors 294 passes through a bulkhead 297 in addition to the bulkhead296. However, in other embodiments, the other conductor 294, each of theconductors 294, or the like can pass through multiple bulkheads betweenthe electrical switching device 200 and the terminals 290.

In an embodiment, the conductor 294 that is furthest from the vent 300can pass through bulkhead 297. A blast guided by the ducts 230 anddirected towards the bulkhead 297 may not have fully expanded and couldhave a pressure high enough to blow past an interface of the conductor294 and the bulkhead 296. However, the bulkhead 297 can redirect theblast such that the blast can further expand, reduce in pressure,temperature, or the like, before the blast reaches an interface exposingthe outside of the electrical switching component. That is, the shockfront of the blast can be guided such that pressure is reduced beforethe blast has an opportunity to escape the electrical switchingcomponent.

Moreover, in an embodiment, the bulkhead 297 can create a substantiallyseparate chamber 299. The chamber 299 can be formed from a curvature ofthe bulkhead 297 towards the bulkhead 296. Other structures such as thecenter bulkhead 254 or the like can create other sides of the chamber299. Accordingly, a blast must travel through multiple chambers,experiencing an expansion out of the duct 230, a constriction whenpassing through a gap 287, another expansion in chamber 299, and so on.Multiple chambers such as chamber 299 can be created such that a blasttravelling towards the terminal 209 can experience such expansions andconstrictions. As a result, the interfaces of the sides, bulkheads,walls, or the like can be more likely to contain the blast and guide itto the intended vent 300.

FIG. 22 is a cross-sectional view illustrating a second chamberaccording to some inventive principles of this patent disclosure. FIG.23 is a cross-sectional view along plane 298 illustrating a wall of thesecond chamber of FIG. 22 according to some inventive principles of thispatent disclosure. In the embodiment of FIG. 21, the bulkheads 299 and296 are illustrated as including gaps 287 and 295 allowing the conductor294 to be assembled in the electrical switching component. In contrast,in the embodiment of FIG. 22, the corresponding gaps are on oppositesides of the conductor 294.

For example, the center bulkhead 254 includes the bulkhead 296. Thebulkhead 296 extends towards the side 234. As described above, a gap 295is present to allow assembly. A tab 291, illustrated in phantom, cansubstantially fill the gap 295, substantially sealing that wall of thechamber 299. In contrast, the gap 287 of the bulkhead 297 is disposed onan opposite side of the conductor 294. Moreover, the bulkhead 297 isdisposed on the side 234, not on the center bulkhead 254 as illustratedin FIG. 21. A tab 291 of the center bulkhead 254 extends to fill the gap297 of the bulkhead 297.

The cross-sectional view along plane 289 is illustrated for bulkhead297. However, the orientation of the gap 295 and the bulkhead 296 are onopposite sides for a similar cross-section. A blast can escape throughthe gaps in such structures. However, a blast travelling along conductor294 will not have a substantially straight path through chamber 299.That is, because of the orientation of the gaps, the blast can changedirection, deposit suspended particles on the walls, and further isolatethe terminal 290 and any wiring from the blast.

FIG. 24 is a block diagram illustrating an example of guiding a blastaccording to some inventive principles of this patent disclosure. Inthis embodiment various components described above are conceptuallyillustrated to show a path traveled by a blast. A case 202 of anelectrical switching device 200 includes the contacts 204 and 206 wherea blast occurs. Walls 216 and 240 contain the blast and, with the case202, guide the blast through the ducts 230 into an expansion chamber298.

The chamber 298 is bounded by the center bulkhead 254, a correspondingside such as side 234, bulkhead 296, bulkhead 256 or 258, circuit board252, and stand-off 270. In one example, a blast can be deflected by thecenter bulkhead 254 or side 234, directed towards the vent 300 bybulkhead 298. In another example, the blast can be deflected by walls256 or 258, and circuit board 252 towards the vent 300. Accordingly, inan embodiment, each of the various walls, bulkheads, circuit boards, andthe like contribute to containing the blast and guiding it towards thevent 300.

Moreover, in an embodiment, the electrical switching component can forma module. That is, the electrical switching device 200, which has itsown case 202, can be encapsulated within the case formed by the variouswalls, bulkheads, and the like described above to form a modularcomponent.

FIG. 25 is a block diagram illustrating various zones according to someinventive principles of this patent disclosure. As described above,walls 256 and 258, and stand-off 270 can substantially isolate portionsof the circuit board 252 from a blast. FIG. 25 illustrates a top view ofthe circuit board 252. Walls 256 and 258 can divide the circuit board252 into two different zones 301 and 302.

Zone 301 can be a high voltage circuit zone. That is, high voltagecircuitry, relays, switches, or the like can be disposed in circuit zone301. For example, various components that may be coupled to theelectrical switching device 200, the conductors 294, or the like withinthe electrical switching component can be coupled to the circuit board252 in zone 301. In addition, circuit zone 301 can include the portionof the circuit board 252 that can deflect a blast as described above.Accordingly, as a blast can create short circuits between a lineterminal of the electrical switching component, circuitry within thezone 301 could be subjected such line voltages. Accordingly, thecircuitry in zone 301 could be exposed to a voltage range including highvoltages.

In contrast, circuit zone 302 can be substantially isolated from theblast. As described above, the walls 256 and/or 258 can prevent anamount of the blast from reaching circuitry within zone 302.Accordingly, the circuitry in zone 302 can be exposed to a voltage rangeincluding maximum voltages lower than that of circuit zone 301. That is,even after a blast, short circuits caused by the blast may not causehigh voltages to be conducted to circuitry in zone 302. Thus, lowvoltage circuitry, processors, interfaces, or the like can be placed inzone 302.

FIG. 26 is a block diagram illustrating additional zones of the circuitboard of FIG. 25 according to some inventive principles of this patentdisclosure. FIG. 24 illustrates the opposite side of circuit board 252.Walls 256 and 258 are illustrated in phantom for reference.

This side of the circuit board 252 includes zones 305 and 306. The zones305 and 306 can be divided by an isolator 303. The isolator 303 can forma division 307 between the zones 305 and 306. The isolator 303 can be avariety of devices. For example, the isolator 303 can be anopto-isolator, a transformer, or the like such that current issubstantially prevented from flowing directly across the isolator 303.

In zone 305, circuitry can be present that does not operate in the highvoltage range of zone 301. However, zone 305 can include through-holecomponents that penetrate the circuit board 252. As a result, thecomponents can have electrical contact with zone 301 on the oppositeside. As a result, in the event of a blast, a short circuit in zone 301can cause a high voltage to appear on circuitry in zone 305.

Accordingly, at least one isolator 303 can allow signals to pass betweenzones 305 and 306. Any high voltage in zone 305 can be contained in zone305. Note that as the blast can be substantially isolated from this sideof the circuit board 252, materials that can create short circuits willlikely not be deposited in either zones 305 or 306. As a result, a shortwill likely not be created across the isolator 303. Thus, the isolator303 can bridge the division 307 of zones 305 and 306.

FIG. 27 is a perspective view illustrating an electrical switchingcomponent according to some inventive principles of this patentdisclosure. In this embodiment, an electrical switching component 310can include a case 311 and a connector 316. An additional connector 318is illustrated; however, any number of connectors can be used.

The connector 316 is disposed on a first end of the case such that theconnector 316 can be coupled to a second connector (not illustrated) ona mounting site 324 by moving the case 311 in a direction 320. That isthe connector 316 is disposed on the case 311 such that movement ondirection 320 can engage the connector 316.

The case 311 includes a retaining structure 312. The retaining structure312 is configured to be constrained such that movement of the case inthe direction 320 is limited. For example, a panel 322 of an enclosurecontaining the electrical switching component 310 can be installed afterthe electrical switching component 310 is mounted on the mounting site324. As a result, the movement of the electrical switching component 310is constrained along direction 320. That is, the mounting site 324 canprevent the electrical switching component 310 from moving in thedirection of the arrow of direction 320 while the plate 322 can beconfigured to prevent the electrical switching component 310 from movingin a direction opposite the arrow of direction 320.

As illustrated, the retaining structure 312 can include a protrusionextending from a surface of the case 311. The plate 322 can be disposedon a side of the retaining structure 312 opposite the mounting site 324.

In another embodiment, the retaining structure 312 can include arecessed region within a surface of the case 311. The recessed regioncan be configured to receive a corresponding tab, protrusion, or otherstructure of the plate 322.

In another embodiment, the retaining structure 312 can include mountinglocations for a fastener. For example, a fastener can include a screw,brad, bolt, nut, or the like. The case 311 can include a threaded holeconfigured to receive a screw, for example. Accordingly, the plate 322can be mounted to the case 311 using the retaining structure 312.

In an embodiment, the electrical switching component 310 can include amanual actuator 314 coupled to an electrical switching device of theelectrical switching component 310 as described above. The manualactuator 314 can be configured to change a state of the electricalswitching device as the manual actuator is actuated in the direction320.

Since the manual actuator 314 can be actuated in the direction 320, theforce applied to actuate the manual actuator 314 has the potential todislodge the electrical switching component 310 from the mounting site324. However, since the retaining structure 312 is coupled with theplate 322, limiting the movement along direction 320, such actuation ofthe manual actuator 314 can reduce a chance that the force applied willdislodge the electrical switching component 310.

FIG. 28 is a cutaway view illustrating an actuator according to someinventive principles of this patent disclosure. The manual actuator 314can include an end 334. The end 334 can be configured to actuate aphotointerruptor 332. The photointerruptor 332 can be disposed on thecircuit board 252 described above. Accordingly, when the manual actuator314 is actuated, such actuation can be sensed. In addition, the manualactuator 314 can be configured to move when the electrical switchingdevice 200 is electrically actuated. That is, when the electricalswitching device 200 is actuated by an electronic signal, the electricalswitching device 200 can cause the manual actuator 314 to be actuated.Such actuation can also be sensed by the photointerruptor 332 andinterpreted as the position of the manual actuator 314 and hence, thestate of the electrical switching device 200. That is, from theposition, a state of the electrical switching device can be sensed. Forexample, not only can an on/off state be sensed, but with anappropriately configured sensor, other states, such as a tripped statecan be sensed.

In an embodiment, the manual actuator 314 need not be present, yet theactuation of the electrical switching device 200 can still be sensed.For example, the manual actuator 314 can be replaced with a linkageconfigured to couple contacts or other structures of the electricalswitching device 200 to the photointerruptor 332. Thus, the actuationcan be sensed without a manual actuator 314. However, in anotherembodiment, such linkages can include the manual actuator 314.

Although a photointerruptor has been described above, other types ofsensors can be used. For example, a mechanical contact sensor that makesor breaks an electrical circuit can be used. A digital position encodercan be used to sense the position of the end 334. Any sensor that cansense position, movement, acceleration, or the like can be used.

As described above, the electrical switching component 310 can have bothhigh voltage circuitry and low voltage circuitry. In an embodiment thehigh voltage circuitry can be substantially isolated from a user. Thatis, a user may be required to remove panels, cases, enclosures, or thelike beyond that used in normal operations to access the high voltagecircuitry.

Accordingly, the retaining structure 312 can be disposed on the case 311to facilitate such isolation from a user. For example, as describedabove, the assembly can have various high voltage circuitry, conductors,or the like. Line 336 conceptually divides the electrical switchingcomponent 310 into high voltage and low voltage regions. At one end ofthe electrical switching component 310 with the terminals 290, highvoltage circuitry is exposed through an opening of the case 311. Atanother end of the electrical switching component 310 with theconnectors 316 and 318, low voltage circuitry is exposed through thecase 311.

The retaining structure 312 can be disposed on the case 311 between suchopenings. Accordingly, when secured by the panel 322 described above orother similar structure, the high voltage electrical circuitry and, inparticular, the exposed contacts such as the terminals 290 of the highvoltage circuitry can be substantially isolated from a user.

FIG. 29 is a perspective view illustrating a case according to someinventive principles of this patent disclosure. In this embodiment, thecase 311 of the electrical switching component 310 includes a protrusion340 extending from a surface of the case 311. The protrusion 340 canextend from a side of the case opposite the retaining structure 312.

The protrusion 340 can be aligned along the direction such that when theprotrusion is disposed in a corresponding opening, the case issubstantially constrained in a second direction 344 substantiallyorthogonal to the first direction 320. The protrusion 340 can be alignedsuch that the case 311 is not substantially constrained when disposed inthe corresponding opening in direction 320.

For example, the opening can be a slot aligned with a long axis indirection 320. The protrusion 340 can have a width in direction 344substantially equal to the width of the slot, while a length of theprotrusion 340 is less than a corresponding length of the slot indirection 320. Thus, the electrical switching component 310 can have arange of motion along direction 320 while being substantiallyconstrained in direction 344.

In an embodiment, the case 311 can include a second protrusion 342. Thesecond protrusion can be disposed on the same side of the case 311 asthe first protrusion 340 opposite the retaining structure 312. Thesecond protrusion 342 can, but need not be shaped similarly to the firstprotrusion. The second protrusion 342 can be similarly formed toconstrain the motion of the electrical switching component 310 whendisposed in a corresponding opening as is the first protrusion 340.

The first protrusion 340 and the second protrusion 342 can be disposedon opposite edges of case 311. For example, the first protrusion 340 canbe disposed on a first edge 341 of the case 311. The second protrusion342 can be disposed on a second edge 343. Although the edges 341 and 343can be on the same side of the case 311 opposite the retaining structure312, the edges 341 and 343 can be on opposite edges of that side.

In an embodiment, the protrusions 340 and 342 can be offset from eachother along direction 320. That is, along the direction of insertion formounting the electrical switching component 310, the protrusions 340 and342 can be offset. However, in other embodiments, the protrusions 340and 342 need not be offset.

In an embodiment, mounting ears 346 can be disposed on the case 311 tomount the electrical switching component 310 to a mounting location. Forexample, the mounting location can have an opening configured to receivethe mounting ears 346.

FIG. 30 is a side view illustrating the protrusion and mounting ear ofFIG. 29. The protrusion 340 can have a height 348 that is greater than aheight 350 of the mounting ear 346. Accordingly, in an embodiment, whenbeing mounted on a mounting site, the protrusion 340 can contact themounting site prior to the mounting ear 346. As a result, when theprotrusion 340 is aligned with a corresponding opening, the protrusion340 can pass through the opening, allowing the mounting ear 346 toapproach the mounting site.

FIG. 31 is a plan view of an example of a mounting site for the assemblyof FIG. 29. In this embodiment, the side of the case 311 opposite theretaining structure 312 is illustrated in phantom. FIG. 31 illustrates astate where the electrical switching component 310 is mounted on themounting site 380, but the mounting ears 346 are not engaged. Themounting site 380 includes openings 370, 372, and 374. The protrusions340 and 342 are disposed in openings 370 and 372, respectively. Themounting ears 346 are disposed in the openings 374.

As described above, the protrusions 370 and 372 can be higher than themounting ears 346. Accordingly, when the electrical switching component310 is brought into contact with the mounting site 380, the contact willbe with the protrusions 340 and 342.

In an embodiment, the openings 370 and 372 can be longer along direction320 than necessary to accommodate a range of motion of the electricalswitching component 310 when the mounting ears 346 are disposed in theopenings 374. That is, a greater amount of misalignment of theprotrusions 340 and 342 relative to an installed location can betolerated with the openings 370 and 372.

Accordingly, the protrusions 340 and 342 can engage with the openings370 and 372 with an amount of misalignment between the mounting ears 346and the openings 374. However, this does not mean that the mounting ears346 cannot engage the openings as the protrusions 340 and 342 can engagewith the openings 370 and 372. If the protrusions 340 and 342 engagewith the openings 370 and 372 with the mounting ears 346 misaligned, themounting ears 346 can contact the mounting site 380 and slide along asthe electrical switching component 310 is moved.

As the protrusions 340 and 342 are engaged with the openings 370 and372, the motion of the electrical switching component 310 isconstrained. Thus, the motion of the assembly, is limited in direction344; however, the motion in direction 320 is possible due to therelative lengths of the protrusions 340 and 372 and the openings 370 and372. The electrical switching component 310 can be moved along direction320 until the mounting ears 346 pass through the openings 374. Theelectrical switching device 310 can then be moved again along direction320 to engage the mounting ears 346 with the mounting site 380.

Although the mounting ears 346 have been used as an example, othermounting structures can be used. For example, clips, hooks, or the likecan be used to mount the electrical switching device 310 to the mountingsite 380.

The inventive principles of this patent disclosure have been describedabove with reference to some specific example embodiments, but theseembodiments can be modified in arrangement and detail without departingfrom the inventive concepts. For example, in some embodiments, a circuitboard may be part of the electrical switching component, while in otherembodiments, a circuit board may be all or part of a chassis to whichthe component is mounted. As another example, the switching device neednot be a simple on-off device, but may provide continuous control suchas that provided by an SCR, triac, transistor, etc. Such changes andmodifications are considered to fall within the scope of the followingclaims.

The invention claimed is:
 1. An apparatus, comprising: an electricalswitching component including an electrical switching device to controlcurrent to a load, a case substantially encapsulating the electricalswitching device, a retaining structure, and a first connector disposedon a first end of the case such that the first connector can be coupledto a second connector on a mounting site by moving the case in a firstdirection, a first protrusion extending from a side of the case oppositethe retaining structure, the first protrusion aligned along the firstdirection such that when the first protrusion is disposed in acorresponding opening, the case is constrained in a second directionsubstantially orthogonal to the first direction; wherein the retainingstructure of the case is configured to be constrained such that movementof the case in a second direction opposite the first direction islimited.
 2. The apparatus of claim 1, further comprising a manualactuator coupled to the electrical switching device and extending fromthe case, the manual actuator configured to change a state of theelectrical switching device as the manual actuator is actuated in thefirst direction.
 3. The apparatus of claim 1, wherein the retainingstructure includes a protrusion extending from a surface of the case. 4.The apparatus of claim 1, wherein the retaining structure includes arecessed region within a surface of the case.
 5. The apparatus of claim1, wherein: the case includes first circuitry constrained to a firstvoltage range and a first opening exposing the first circuitry; the caseincludes second circuitry constrained to a second voltage rangeextending higher than the first voltage range and a second openingexposing the second circuitry; and the retaining structure is disposedon the case between the first opening and the second opening.
 6. Theapparatus of claim 1, the apparatus further comprising: a secondprotrusion extending from the side of the case opposite the retainingstructure, the second protrusion aligned along the first direction suchthat when the second protrusion is disposed in a corresponding opening,the case is constrained in a second direction substantially orthogonalto the first direction; wherein: the first protrusion is disposed on afirst edge of the side of the case opposite the retaining structure; thesecond protrusion is disposed on a second edge of the side of the caseopposite the retaining structure; and the first edge is opposite thesecond edge.
 7. The apparatus of claim 6, wherein the first protrusionand the second protrusion are offset from each other along the firstdirection.
 8. The apparatus of claim 7, wherein: the case is an outercase; the electrical switching device comprises: an inner case, aplurality of contacts disposed in the inner case, and an opening in theinner case disposed to expose the contacts; and the outer case isarranged to duct a blast from the opening of the inner case of theelectrical switching device to a flame-resistant material to at leastpartially contain the blast.
 9. A method, comprising: moving anelectrical switching component in a first direction to engage anelectrical switching component with a mounting site; and engaging apanel with a retaining structure of the electrical switching componentsuch that movement of the electrical switching component is constrainedalong a second direction opposite the first direction.
 10. The method ofclaim 9, further comprising: applying a force substantially along thedirection to actuate a manual actuator of the electrical switchingcomponent; and opposing at least a part of the force by the plate. 11.The method of claim 9, the method further comprising: moving theelectrical switching component in a third direction substantiallyorthogonal to the first direction; aligning at least one protrusion ofthe electrical switching component with an opening of the mounting sitein response to the movement of the electrical switching component in thethird direction; and engaging a mounting structure of the electricalswitching component to the mounting site by moving the electricalswitching component along the first direction.
 12. A system comprising:one or more electrical switching components, each electrical switchingcomponent including a first electrical connector and a retainingstructure; an enclosure including one or more mounting sites forengaging the one or more electrical switching components, and a paneloperatively coupled and decoupled from the enclosure, the panel beingarranged and configured to contact the retaining structure of eachelectrical switching component when the panel is coupled to theenclosure; and one or more second electrical connectors, each secondelectrical connector operatively associated with one of the one or moremounting sites and arranged and configured to engage a corresponding oneof the one or more the first electrical connectors when the electricalswitching component is moved in a first direction while engaging themounting site; wherein the mounting site is configured to constrain eachelectrical switching component from moving in the first direction, andthe panel is configured to constrain each electrical switching componentfrom moving in a second direction opposite the first direction when thepanel is contacting the retaining structure.
 13. The system of claim 12wherein the one or more electrical switching components and the mountingsite are configured to constrain motion of the electrical switchingcomponents in a third direction substantially orthogonal to the firstand second directions.
 14. The system of claim 13 wherein each of theone or more electrical switching components includes a protrusion andeach of the mounting sites includes a first opening configured toreceive the protrusion and constrain motion of the correspondingelectrical switching component in the third direction.
 15. The system ofclaim 14 wherein each of the one or more electrical switching componentsincludes a mounting structure to mount the electrical switchingcomponent to one of the mounting sites when the electrical switchingcomponent is moved in the first direction.
 16. The system of claim 15wherein the protrusion has a height that is greater than a height of themounting structure such that the protrusion can contact the mountingsite prior to the mounting structure when the electrical switchingcomponent is engaged with the mounting site.
 17. The system of claim 16wherein the protrusion can engage the first opening with an amount ofmisalignment between the mounting structure on the electrical switchingcomponent and a second opening on the mounting site configured toreceive the mounting structure.
 18. The system of claim 17 wherein, ifthe protrusion engages the first opening with the mounting structuremisaligned with the second opening, the electrical switching device canbe moved in the first direction until the mounting structure aligns withthe second opening.
 19. The system of claim 12 wherein the one or moreelectrical switching components each includes a mounting structure tomount the electrical switching components to the mounting sites when theone or more electrical switching component are moved in the firstdirection.
 20. The system of claim 19 wherein the mounting structurecomprises a mounting ear and each of the mounting sites includes anopening configured to engage the mounting ear when the one or moreelectrical switching components are moved in the first direction.
 21. Anapparatus, comprising: an electrical switching component including anelectrical switching device to control current to a load, a casesubstantially encapsulating the electrical switching device, a retainingstructure, and a first connector disposed on a first end of the casesuch that the first connector can be coupled to a second connector on amounting site by moving the case in a first direction a first protrusionextending from a side of the case opposite the retaining structure;wherein the retaining structure of the case is configured to beconstrained such that movement of the case in a second directionopposite the first direction is limited; and wherein the case includes:first circuitry constrained to a first voltage range and a first openingexposing the first circuitry; second circuitry constrained to a secondvoltage range extending higher than the first voltage range and a secondopening exposing the second circuitry; and the retaining structure isdisposed on the case between the first opening and the second opening.22. The apparatus of claim 21, further comprising a first protrusionextending from a side of the case opposite the retaining structure, thefirst protrusion aligned along the first direction such that when thefirst protrusion is disposed in a corresponding opening, the case isconstrained in a second direction substantially orthogonal to the firstdirection.
 23. The apparatus of claim 22, the apparatus furthercomprising: a second protrusion extending from the side of the caseopposite the retaining structure, the second protrusion aligned alongthe first direction such that when the second protrusion is disposed ina corresponding opening, the case is constrained in a second directionsubstantially orthogonal to the first direction; wherein: the firstprotrusion is disposed on a first edge of the side of the case oppositethe retaining structure; the second protrusion is disposed on a secondedge of the side of the case opposite the retaining structure; and thefirst edge is opposite the second edge.
 24. The apparatus of claim 23,wherein the first protrusion and the second protrusion are offset fromeach other along the first direction.
 25. The apparatus of claim 21,wherein: the case is an outer case; the electrical switching devicecomprises: an inner case, a plurality of contacts disposed in the innercase, and an opening in the inner case disposed to expose the contacts;and the outer case is arranged to duct a blast from the opening of theinner case of the electrical switching device to a flame-resistantmaterial to at least partially contain the blast.
 26. The apparatus ofclaim 21, further comprising a manual actuator coupled to the electricalswitching device and extending from the case, the manual actuatorconfigured to change a state of the electrical switching device as themanual actuator is actuated in the first direction.
 27. The apparatus ofclaim 21, wherein the retaining structure includes a protrusionextending from a surface of the case.
 28. The apparatus of claim 21,wherein the retaining structure includes a recessed region within asurface of the case.